The present invention relates to a new and distinct variety of walnut tree Juglans regia which has been denominated varietally as ‘Forde,’ and more particularly to such a walnut tree which has a harvest date three to eight days earlier than the walnut tree variety ‘Chandler’ (U.S. Plant Pat. No. 4,388) and which further produces a walnut that is jumbo in size with light colored kernels and which can be processed in shell or cracked.
It has long been recognized as desirable to provide walnut trees bearing large crops which are ripe for commercial harvesting and shipment midseason and exhibit low susceptibility to walnut blight. The tree of the present variety, ‘Forde,’ produces a nut which is similar in some respects to common walnut tree varieties such as ‘Chandler,’ (U.S. Plant Pat. No. 4,388). However, the new variety is ready for harvest up to eight days before ‘Chandler,’ and ten days after the common reference cultivar ‘Payne’ (unpatented).
The new Juglans regia walnut tree of the present invention was created at Davis, Calif. in 1995 by a controlled cross of the cultivars ‘Chico’ and ‘UC 61-25,’ also known as ‘Lara’ (not patented). ‘Forde’ differs from ‘Chico’ in having larger nuts which are easier to remove from the shell, a later harvest and a more vigorous tree. ‘Forde’ differs from ‘UC61-25’ in having much lighter kernel color, a smoother shell, and unlike ‘UC61-25’, ‘Forde’ is protogynous. The pedigree is illustrated (FIG. 1).
Seeds from the cross were planted and the resulting 40 trees were carefully observed along with other trees in the walnut breeding program. When they began to bear nuts, data were collected annually on leafing date, first peak and last female flower bloom, first, peak and last male bloom, blight severity and yield (Table 1). Nuts were sampled, cracked, and data was collected on shell appearance, shell thickness, shell integrity, shell strength, nut weight, kernel weight, percent kernel, ease of kernel removal, kernel color, and percent kernel shrivel (Table 2). A single tree was selected from among progeny of this controlled cross based on its superior attributes. This selection was originally designated ‘UC95-26-37,’ and is now designated ‘Forde’ after Harold Forde, a University of California walnut breeder from 1948 to 1978.
The new cultivar ‘Forde’ was originally asexually reproduced by grafting in Davis, Calif., Parlier, Calif., and Chico, Calif. The new cultivar of the present invention has been propagated by grafting at Davis, Calif. on ‘Paradox’ hybrid rootstock. The distinctive characteristics of the new cultivar have been found to be stable and are transmitted to the new trees when asexually propagated. ‘Forde’ is stable and reproduces true to type.